Jackfruit mature 3 to 8 months from flowering.
A dull hollow sound is produced when the fruit is tapped with your knuckle.
The last leaf of the peduncle yellows.
Fruit spines become well developed and wider spaced and soften.
The spines yield to moderate pressure.
An aromatic odour develops.
Picking time depends on whether the fruit will be used at home or sold.
Fruit intended to be eaten soon should be harvested when the rind is fairly soft, the peduncle leaves turn yellow and the fruit has an aromatic odour.
Fruit intended for sale should be firm with no aroma but the leaf nearest the fruit must be starting to turn yellow and the spines set far apart. The flesh at this stage is crispy and pale yellow.
The quantity of latex decreases as the fruit ripens. Try to cut a fruit that is green and you will have latex all over you. Cut into an over ripe fruit and there is almost no latex. If you do get the sap on your hands you can easily get it off using lanoline soap, the kind they use in industry.
After ripening, they turn brown and deteriorate rather quickly. Cold storage trials indicate that ripe fruits can be kept for 3 to 6 weeks at 52° to 55° F and relative humidity of 85% to 95%.
You can also make 3 shallow cuts in the fruit a few days before you plan to cut it down which will let some of the latex drain out.
Use rubber surgical gloves and coat knives with olive oil when cutting up the fruit just in case of latex.
If the fruit is too high up to check if it is ripe, slap it with a long pole to hear that dull sound.
Ripening can be accelerated by putting whole fruit into a closed 20 litre bucket 5-7 gallon (20-30 quart)